Injection Molding Apparatus and Method of Constructing the Injection Molding Apparatus

ABSTRACT

A hand operated injection molding apparatus constructed from prefabricated sub-assemblies and a desired mold clamping means attached to a main support structure, and then electrically integrated with each other

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a continuation-in-part application of the continuation-in-partapplication U.S. Ser. No. 12/390,439 filed on Feb. 21, 2009, which iscurrently pending and claims the priority of expired provisionalapplication U.S. Ser. No. 61/150,863 filed on Feb. 9, 2009 andnon-provisional application U.S. Ser. No. 11/829,873, now U.S. Pat. No.7,494,332, filed on Jul. 27, 2007 claiming the priority of expiredprovisional application U.S. Ser. No. 60/834,600 filed on Aug. 1, 2006.

BACKGROUND

Hand operated injection molding machines have been around for decades.One of the first machines commercialized was built by Arburg, Inc. in1954. It was originally designed for internal use to fabricate aparticular part. However, in 1956 the company decided to sell themachines outright, ultimately selling over 10,000 units. Although theearly Arburg machines were probably fine machines in their day, theirmode of construction wouldn't provide the manufacturing versatilityneeded in today's globally competitive environment.

More recently, within the last 35 years or so, a number of otherhand-operated injection molding machines have been built and marketed byvarious companies. For example, Educational Machinery Corporation (EMCO)produced a hand-operated injection molding instructional device, whichwas primarily sold to schools to demonstrate the basic process ofinjection molding. Honetech, Inc. produced the Honejector InjectionMolder, which was very similar to the EMCO machine, except for minordifferences in style. NRK Mfg. & Engineering Co. produced the PlasticorJr. along with some molds to make plastic toy figures. Presumably theNRK machine was intended as a novelty or toy. There have also beennumerous inventors and entrepreneurs who have built their ownhand-operated injection molding machines over the years, with variouslevels of success. Many of these machines have been very basic indesign, where flat and angled metal plates were simply welded togetherto construct the support frame, and then the individual components werethen attached to it one after another until the machine is built. Apopular book on the market, Secrets of Building An Injection MoldingMachine (ISBN 1-878087-19-3) describes in detail how to build a basicinjection molding machine exactly that way. What is missing from theprior art machines heretofore is that none are constructed in a way thatfacilitates an efficient and economical method of mass production. Whatis also missing from the prior art machines heretofore is that they lackthe functional improvements and manufacturing versatility demanded intoday's marketplace. It would therefore be desirable and advantageous toprovide an improved injection molding machine apparatus and method ofconstructing the same to obviate the prior art shortcomings.

SUMMARY OF THE INVENTION

The present invention is a hand-operated injection molding apparatus andan efficient, economical method of constructing the same. Also inventedare a number of functional improvements that may be employed with theinvented apparatus if desired.

Accordingly, one object of the present invention is to provide ahand-operated injection molding apparatus that is efficiently andeconomically constructed.

Another object of the present invention is to provide an efficient,economical, and versatile method of construction for a hand-operatedinjection molding apparatus that facilitates mass production.

Another object of the present invention is to provide a hand-operatedinjection molding apparatus with additional functional improvements thatmay be employed if desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of invented apparatus.

FIG. 2 is a perspective view of the stand.

FIG. 3 is an exploded perspective view of the heat unit sub-assembly.

FIG. 4 is an exploded perspective view of the handle sub-assembly.

FIG. 5 is an exploded perspective view of the control box sub-assembly.

FIG. 6 is an exploded perspective view of the mold-clamping means.

FIG. 7 is an exploded perspective view of the invented apparatus withadditional hardware.

FIG. 8 is a perspective view of the assembled invented apparatus.

FIG. 9 is an exploded perspective view of an adjustment means, heaterblock, bracket, and probe port.

FIG. 10 is a perspective view of the invented apparatus with an explodedview of additional components and improvements.

FIG. 11 shows FIG. 10 with the exploded components now attached.

FIG. 12 is a perspective view of the invented apparatus with a moldsecured by the mold clamping means.

FIG. 13 illustrates an alternative heater block construction with aremovably secured injection tube.

FIG. 14 illustrates an alternative control box sub-assembly constructionthat accommodates attachment of an electronic temperature controller anddisplay means.

FIG. 15 illustrates the heat unit sub-assembly with a removably securedinjection tube and gripping means.

FIG. 16 illustrates removal of the injection tube from the heater blockusing the gripping means.

DETAILED DESCRIPTION Overview

In the preferred embodiment, and as shown by FIG. 1, the inventedapparatus 1 comprises at least; a main support structure, hereafterreferred to as the stand 2 for brevity; a heat unit sub-assembly 20; ahandle sub-assembly 40; a control box sub-assembly 60; and a moldclamping means 80. The said sub-assemblies 20, 40, 60 and the moldclamping means 80 are each attached to the stand 2 in any desired order,and then the heat unit sub-assembly 20 and the control box sub-assembly60 are electrically integrated with each other to complete constructionof the invented apparatus 1.

In the subsequent sections: the stand 2, shown by FIG. 2, will first bedescribed in detail. Then, the heat unit sub-assembly 20, shown by FIG.3, will be described in detail. Then the handle sub-assembly 40, shownby FIG. 4 will be described in detail. Then the control box sub-assembly60, shown by FIG. 5 will be described in detail. Then the mold clampingmeans 80, shown by FIG. 6, will be described in detail. Then it will bedescribed how sub-assemblies 20, 40, 60 and the mold clamping means 80are each attached to the stand 2. Then it will be described how thesub-assemblies 20 and 60 are electrically integrated with each other tocomplete construction of the invented apparatus 1. Then it will bedescribed how the invented apparatus 1 may comprise various othercomponents and functional improvements, if desired. Then finally, abrief discussion of how the invented apparatus 1 operates.

Accordingly: Stand

FIG. 2 shows the stand 2, which defines the basic framework of theinvented apparatus 1 and provides the main support structure for thesub-assemblies 20, 40, 60, and the mold clamping means 80. In thepreferred embodiment illustrated, the stand 2 is a unitary casting madeFrom a desired metal. In an alternative embodiment (not shown), thestand 2 is fabricated from multiple parts and then assembled together.For example, in an alternative embodiment, the base portion and theupright portions may be separately fabricated, but then fastenedtogether. Referring back to the illustrated embodiment, the stand 2 ismachined with various holes, slots, and flattened surfaces toaccommodate attachment of the sub-assemblies 20, 40, 60, the moldclamping means 80, and additional components if desired. The stand 2 mayalso be painted or powder coated if desired. Specific areas of the stand2 referred to later in this detailed description are as follows: base 3,front wall 4, back wall 5, side wall 6, nose 7, nose extension 8, andback fin 9. As is apparent by viewing FIG. 2 the back fin 9 portion ofthe stand 2 extends above the rest of the structure, providing certainutility advantages during operation of the invented apparatus 1, whichis later described in more detail.

Heat Unit Sub-Assembly

It should first be clarified, the term “heat unit” used to characterizethis sub-assembly was chosen for brevity. The said sub-assembly actuallyincludes means for not only heating a thermoplastic material, but alsofor containing it and injecting it. So, it should properly be considereda “thermoplastic heating and injection unit” sub-assembly.

More particularly, the heat unit sub-assembly 20 of the inventedapparatus 1 comprises at least: a support means; a means for containinga thermoplastic material; a means for heating a thermoplastic material;a means for transferring heat; a means for directing the flow of athermoplastic material; a means to actuate motion; a means to sensetemperature; and a means for electrical connection to other componentsof the invented apparatus 1.

Accordingly, as shown in FIG. 3, one preferred embodiment of the heatunit sub-assembly 20 comprises at least the following componentsassembled together in any desired configuration: the heater block 21;the injection tube 22; the injection nozzle 23; the support means,comprising the horizontal support member 24 and a vertical supportmember 25 in combination; the actuating means 26; the heating element27; the temperature sensing means 28; and the electrical connectionmeans 38.

In one preferred construction: the heater block 21 is machined from analuminum billet to a desired specification; the injection tube 22 isinserted into a predrilled hole 29 in the heater block 21 and securedtherein, permanently or removably, by any desired means, such as a hightemperature epoxy cement, or mechanically, by means of a locking member30, which as illustrated, may be a set screw or a tubular type springclip inserted into a desired hole 31 in the heater block 21 until itmakes contact with the injection tube 22; the injection nozzle 23 screwsinto the bottom portion of injection tube 22, or alternatively, into atapped hole in the heater block 21 directly beneath the insertedinjection tube 22; each heating element 27 is inserted into eachpredrilled hole 32 in the heater block 21; the temperature sensing means28 is placed in close communication with the heater block 21. The saidtemperature sensing means 28 may be of any desired type, such as aresistance temperature device, commonly referred to as an RTD, which areavailable in numerous different configurations. If desired, thetemperature sensing means 28 may also comprise a controlling means,allowing it to both sense the temperature and control it. Thetemperature sensing means 28 shown in FIG. 3 is a bi-metal typethermostat attached to the heater block 21 by means of screws 33; eachpost 37 of heater block 21 is positioned on top of each actuating means26, which as illustrated are two compression springs. From above theheater block 21, each vertical support member 25 is inserted into eachpre-drilled hole 34 in the post 35, also inserting it through theunderlying actuating means 26 until the larger head portion 36 of thesaid vertical support member 25, is resting on top of the heater blockpost 35. Each vertical support member 25 is then attached to eachhorizontal support member 24, thereby captivating and slightlycompressing each actuating means 26 between the horizontal supportmember 24 and bottom surface of the heater block post 35. The said holes34 may be slightly counter bored if desired (not shown) to facilitateproper seating of the head portion 36 of the vertical support member 25and partial recessing the actuating means 26 into the post 35 frombelow. Once each horizontal support member 24 and each vertical supportmember 25 are attached together, they in combination provide the supportmeans for the heater block 21 and actuating means 26, and also serve tokeep the said components in alignment during operation of the inventedapparatus 1. Each horizontal support member 24 in this preferredembodiment is also threaded 37 at one end to facilitate easy attachmentof the constructed heat unit sub-assembly 20 to the stand 2, which willbe described later.

After the components of the heat unit sub-assembly 20 are attachedtogether, the appropriate electrical connections are made between them,and the electrical connection means 38 is provided and attached,arranged, or otherwise created and electrically integrated with the saidcomponents. The said means 38 is designed to facilitate easy electricalintegration of the heat unit sub-assembly 20 with other components ofthe invented apparatus 1. In the illustrated embodiment, the electricalconnection means 38 is an arrangement of wires extending from desiredcomponents of the heat unit sub-assembly 20. As shown, the saidelectrical connection means 38 may also have a plug 39 type terminationif desired.

It shall be appreciated, although certain components of the heat unitsub-assembly 20 are described here as being used in multiple, it is notintended to be a limitation. Such duplication could easily be avoided ifdesired to suit a particular alternative construction. For example, asingle heating element 27 that coils around the injection tube 22 may beemployed instead of the two cartridge type heaters illustrated.

It shall also be appreciated, although this preferred embodimentdescribes each component of the heat unit sub-assembly 20 as first beingindividually fabricated or otherwise individually provided, inalternative preferred embodiments, certain components may be unifiedwith other components at the time they are manufactured, and suchinitial component separation is not intended to be a limitation. Forexample, if the heater block 21 is fabricated as a casting rather thanbeing machined from a billet, the injection tube 22 could easily beembedded into it during the casting operation. Indeed, both theinjection tube 22, and a coil type heating element 27 could be embeddedduring casting of the heater block 21 if desired.

Furthermore, in an alternative construction, as illustrated in FIG. 13,the heater block 21 may have a receiving slot 94 rather than apredrilled hole 29 to accommodate insertion of the injection tube 22.Whereas, in this embodiment, the said tube 22 is mechanically secured tothe heater block 21 by means of a metal insert 95 fitted into the slot94 and two dowel pins 96. The said dowel pins 96 serve as the lockingmembers, and are inserted through holes 97 in the metal insert 95 andholes 98 in the heater block 21. The said holes 97 and 98 are arrangedin alignment with each other to accommodate the same; the injectionnozzle 23 secures to the bottom of the injection tube 22 by a means of aset screw 99, or other desired fastening means; the temperature sensingmeans 28 mounts to the heater block 21 by means of screws 100, andaccommodates electrical attachment of a remotely located temperaturecontrolling means.

One advantage of constructing the apparatus according to the preferredembodiment of FIG. 13 rather than FIG. 3, is that it allows the user toeasily remove the injection tube 22 (and nozzle 23, if secured thereto)from the heater block 21 for repair or replacement. Another advantage ofconstructing the apparatus according to the preferred embodiment of FIG.13 rather than FIG. 3, is that when a temperature control means isremotely located from the sensing means 28, it allows more flexibilityin choosing the type and size of the said control means.

After construction is complete, the heat unit sub-assembly 20 provides:a means to hold a thermoplastic material, the injection tube 22; a meansto generate heat, the heating element 27; a means to transfer the heatto the thermoplastic material, the heater block 21; a means to controlor otherwise direct the flow of the melted thermoplastic, the injectionnozzle 23; a means to actuate movement, the actuating means 26, whichwill be explained later when describing how the invented apparatusoperates; a means to sense temperature, the temperature sensing means28; a means to support the other components of the sub-assembly 20 andfacilitate their attachment to the stand 2, the support members 24 and25 in combination; and an electrical connection means, the wire assembly38.

It shall be appreciated; the heat unit sub-assembly 20 may also compriseadditional components and functional improvements if desired, which willbe described later in this detailed description.

Handle Sub-Assembly

In one preferred embodiment, the handle sub-assembly 40 comprises atleast: a handle means; a ram means; a swivel means; a hinge means; and asecuring means.

Accordingly, as shown in FIG. 4, one preferred construction of thehandle sub-assembly 40 comprises at least the following componentsassembled together in any desired configuration: the handle 41; theclevis 42; the injection ram 43; the hinge members 44; the catch pin 45.Whereas, the handle 41 is machined from metal to a desired specificationto accommodate attachment of the hinge members 44, the clevis 42, andthe catch pin 45; the hinge members 44 are fabricated from metal and aresecured to the handle 41 by means of a hinge pin 46 and cotter 47 orsimilar bolt and nut, such that the said hinge members 44 may swivelfreely on the handle 41; the clevis 42 is preferably fabricated frommetal and attaches to the handle 41 by means of a clevis pin 48 andcotter pin 49, such that the said clevis 42 may swivel freely on thesaid handle 41, and be easily removed if desired; the injection ram 43is fabricated from precision ground steel or stainless steel rod and iscoated with a non-stick material. The threaded end 50 of the saidinjection ram 43 is screwed into a tapped hole in the bottom surface(not visible) of the clevis 42; the catch pin 45, which in thisillustration is a partially threaded pin, is screwed into the tappedhole 51 in the back surface of the handle 41. It should be noted at thispoint, as shown in FIG. 7, the said catch pin 45 is designed tointerlock with a catching means 92 that mounts near the tip of the backfin 9 of the stand 2, so when the handle 41 is lifted up duringoperation of the invented apparatus 1, the said catch pin 45 interlockswith the said catching means 92 and keeps the handle 41 held in itsupright position until the user pulls down on it to release it. In analternative embodiment (not shown), both the catch pin 45 and catchingmeans 92 are embodied in the handle sub-assembly 40 together providing areleasable interlocking means, and making the stand 2 mounted catchingmeans 92 unnecessary.

After construction is complete, the handle sub-assembly 40 comprises atleast: a handle means, the handle 41; a ram means, the injection ram 43;a swivel means, the clevis 42; a hinge means, the hinge members 44; anda securing means, the catch pin 45.

It shall be appreciated, although certain components of the handlesub-assembly 40 are described above as being used in multiple, it is notintended to be a limitation. Such duplication could easily be avoided ifdesired in an alternative construction. For example the two hingemembers 44 shown could easily be fabricated as a single component,joined by a bridge between them. The said bridge may also serve tostructurally reinforce the said hinge member 44.

It shall also be appreciated, although this preferred embodimentdescribes each component of the handle sub-assembly 40 as beingindividually fabricated or otherwise individually provided, inalternative preferred embodiments, certain components may be unifiedwith other components at the time they are manufactured, and suchinitial component separation is not intended to be a requirement. Forexample, if the hinge members 44 shown are instead fabricated as asingle component, and have a reinforcement bridge between them as justmentioned, that said bridge may also be designed to function as thecatching means 92 for the catch pin 45.

It shall further be appreciated; the handle sub-assembly 40 may alsocomprise additional components and functional improvements if desired,which are described later in this detailed description

Control Box Sub-Assembly

In the preferred embodiment, the control box sub-assembly 60 serves asthe main junction point for the electrical circuitry of the inventedapparatus 1 and comprises at least: an enclosure means; a power controlmeans; a cord member; and a means for electrical connection to othercomponents of the invented apparatus 1.

Accordingly, as shown in FIG. 5, one preferred construction of thecontrol box sub-assembly 60 comprises at least: the enclosure 61, whichhas two parts, the housing 61(a) and the face plate 61 (b); a firstpower control means, the power switch 62; a second power control means,the circuit breaker 63; a cord member, the power cord 64, and anelectrical connection means 66.

The circuit breaker 63 is secured inside the housing 61(a), and has areset button 65 that is accessible from outside the enclosure 61. Thepower switch 62 is mounted to the face plate 61(b) and has a switchportion that is accessible from outside the enclosure. The power cord 64wires, opposite the plug end, are inserted through a desired hole in thecontrol box housing 61(a). After the components are attached orotherwise properly positioned, the appropriate electrical connectionsare made between them, and the electrical connection means 66 isattached, arranged, or otherwise created and electrically integratedwith the said components. The said connection means 66 is designed tofacilitate easy electrical integration of the control box sub-assembly60 components with external components. In the illustrated embodiment,the said electrical connection means 66 is an arrangement of wiresextending from desired components of the control box sub-assembly 60through a desired hole 67 in the enclosure 61. As shown, the said means66 may have a plug 68 type termination if desired. The said plug 68 mayalso be a type that fixedly mounts to the enclosure by press-fitting itinto the said hole 67 if preferred. After the internal electricalconnection are made, the face plate 61(b) portion of the enclosure 61attaches to the housing 61(a) portion of the enclosure 61 by means ofscrews 69. Threaded studs 70 are welded to the back surface of thehousing 61(a) to accommodate later attachment of the control boxsub-assembly 60 to the stand 2. In an alternative preferred embodiment,the control box sub-assembly 60 is more elaborate, and accommodates theattachment of an electronic temperature control and display means.

Accordingly, as illustrated in FIG. 14, the control box sub-assembly 60comprises at least an enclosure 61; a power control means 63; a cordmember 64 for connection to a desired power source; an electricalconnection means 66 for connection to the other components of theinvented apparatus 1; and a means to accommodate electricalcommunication between the control box sub-assembly 60 and a temperaturecontrol and display means 101, which as illustrated is a plug-in typereceptacle 103 and an electrical wire 102.

If desired, the said enclosure 61 of the control box sub-assembly 60 mayalso comprise a bracket or similar holding means (not shown) to retainthe temperature control and display means 101 when it's not in use.

It shall be appreciated, although certain components of the control boxsub-assembly 60 are described above as being used in multiple, it is notintended to be a limitation. Such duplication could easily be avoided ifdesired in an alternative construction. For example, instead of having afirst power control means, the power switch 62, and a second powercontrol means, the circuit breaker 63, both embodied in the control boxsub-assembly 60, the circuit breaker 63 could alternatively be comprisedas a component of the heat unit sub-assembly 40.

It shall also be appreciated; the control box sub-assembly 60 maycomprise additional components and functional improvements, which willbe described in a later section of this detailed description.

Mold Clamping Means

In the preferred embodiment, the mold clamping means 80 secures aninjection mold to the invented apparatus 1, and comprises at least: ahandle means; an actuating member; and a push plate.

As shown in FIG. 6, one preferred embodiment of the mold clamping means80 comprises at least: the handle means 81, which as shown, is a visehandle fabricated from steel with plastic balls for easy gripping; theactuating member 82, which as shown, is a steel threaded rod; the pushplate 83, which as shown is an iron casting. Whereas, the actuatingmember 82 is secured to the handle means 81 by screwing it into athreaded hole 84 in the hub of the said handle means 81 and thensecuring it by means of a roll pin 85 that press-fits into a drilledhole 87 in the said hub. The push plate 83 is secured to the actuatingmember 82 by means of a screw 86. However, it should be noted, as isevident by viewing FIG. 7, after the actuating member 82 is attached tothe handle means 81, they must first be screwed into the threadedthrough hole 19 in the front wall 4 of the stand 2 before the push plate83 is secured to the actuating member 82.

It shall be appreciated; the mold clamping means 80 may have alternativeconstructions without departing from the spirit of the invention. Forexample, the actuating member 82 could simply push forward and retractto clamp the mold, such as in a toggle type mold clamping means (notshown). Whereas, in that embodiment, the handle means 81 operates in alever fashion to clamp the mold, rather than a turning motion, and thepush plate 83 is typically fabricated as a round disc that screws ontothe end of the actuating member 82 by means of a screw 86.

It shall also be appreciated the handle sub-assembly 80 may compriseadditional components and functional improvements if desired, which willbe described later in this detailed description

Method of Constructing the Invented Apparatus

In the preferred embodiment, the invented apparatus 1 is constructed byattaching the heat unit sub-assembly 20, the handle sub-assembly 40, thecontrol box sub-assembly 60, and the mold clamping means 80 to the stand2 in any desired order, and then electrically integrating the heat unitsub-assembly 20 with the control box sub-assembly 60.

More particularly, and as shown in FIG. 7, one preferred method ofconstructing the invented apparatus 1 is as follows: the heat unitsub-assembly 20 is attached to the back wall 5 of the stand 2 bysecuring the two horizontal support members 24 to the said back wall 5.Whereas, a first nut 12 is screwed onto the threaded end 37 of eachhorizontal support member 24. The horizontal support members 24 are theninserted through corresponding holes 11 in the back wall 5, so theirthreaded ends 37 extend through the said wall 5 to the other side. Asecond nut 13 is then attached to each said threaded end 37 from behindthe said wall 5, thus securing the heat unit sub-assembly 20 to the backwall 5. By adjusting the relative position of the nuts 12 and 13 alongthe threaded portion 37 of the support member 24, the position of theheat unit sub-assembly 20 may be adjusted relative to the back wall 5;the handle sub-assembly 40 is positioned over the stand 2 and lowered sothe injection ram 43 inserts through the reamed hole 14 in the nose 7 ofthe stand 2 until the clevis 42 rests on top of the said nose 7. Thefree end of the hinge members 44 are secured to the back fin 9 by meansof a bolt 15 or similar pin, such that the said back fin 9 is interposedbetween the said two hinge members 44. A nut 16 or similar locking meanssecures the said bolt 15 in place; the control box sub-assembly 60 issecured to the back fin 9 of the stand 2 by inserting the threaded studs70 extending from the back surface of the control box housing 61(a)through desired holes 17 in the back fin 9, and then attaching nuts 18to them from the opposite side of the said back fin 9; the handle means81 and actuating member 82 of the mold clamping means 80, having alreadybeen attached to each other, are screwed into the threaded through thehole 19 in the front wall 4 of the stand 2, and then attached to thepush plate 83 by means of a screw 86. Alternatively, the mold clampingmeans 80 may bolt directly to the base 3 of the stand 2 if it is analternative toggle type mold clamping means previously described (notshown). Now that the sub-assemblies 20, 40, 60 and the mold clampingmeans 80 are attached to the stand 2, the heat unit sub-assembly 20 andthe control box sub-assembly 60 are electrically integrated with eachother by joining together the electrical connection means 38 of the heatunit sub-assembly 20 with the electrical connection means 66 of thecontrol box sub-assembly 60. In the embodiment shown, the saidconnection means 38 and 66 both have a plug type terminations 39 and 68respectively, allowing the said means 38 and 66 to be joined togethersimply by plugging them into each other. Typically, in the embodimentshown, the electrical connection means 66 and attached plug 68 are fedthrough the slotted hole 10 in the back wall 5 of the stand 2 to reachthe connection means 38 and attached plug 39. However, as describedbefore, if the electrical connection means 66 employs a plug 68 thatfixedly mounts to the control box housing 61(a), essentially serving asa plug-in receptacle, obviously the electrical connection means 38 andattached plug 39 would instead need to be fed through the said hole 10to reach that said receptacle type plug 68.

Now that the sub-assemblies 20, 40, 60 and the mold clamping means 80have been attached to the stand 2, and the heat unit sub-assembly 20 andcontrol box sub-assembly 60 have been electrically integrated with eachother, construction of the invented apparatus 1 is now complete, asshown in FIG. 8.

The end result is a hand operated injection molding apparatusconstructed from prefabricated sub-assemblies and a desired moldclamping means attached to a main support structure, and thenelectrically integrated with each other. This novel method ofconstruction allows a manufacturer to provide many alternativeembodiments of a desired sub-assembly without having to substantiallymodify the rest of the apparatus. For example, in the illustratedpreferred embodiment: the control box sub-assembly 60 could be easilysubstituted with another one that is more complex, because after thesaid sub-assembly 60 is constructed, it simply attaches to the standwith two nuts and then plugs into the heat unit sub-assembly 20;Likewise, the heat unit sub-assembly 20 could be constructed in manyalternative embodiments, having various degrees of complexities and/orplastic holding capacities, because after the said unit 20 isconstructed, it simply attaches to the stand with nuts, and then plugsinto the control box sub-assembly 60; the handle sub-assembly 40 couldalso be easily substituted with a more elaborate embodiment, such as onehaving a built-in interlocking means previously described, or a morecomplex handle that is extendible in length, because after the said unit40 is constructed, it simply attaches to the back fin 9 of the stand 2with a single bolt 15 and nut 16. Even the stand 2 itself could besubstituted with an alternative embodiment without significantdifficulty, since the sub-assemblies 20, 40, 60 attach to it withminimal integration. Such an advantage would be particularly attractiveto someone who wishes to produce the apparatus 1 as a private labelmanufacturer for a number of different distributors. Whereas, the saidmanufacturer could provide each distributor with a slightly differentconstruction of the stand 2, to distinguish each one in the marketplace.

It shall be appreciated; this disclosed method of construction alsofacilitates economical mass production, because it allows eachsub-assembly to be manufactured independently, wherever it can be donemost cost effectively. It shall also be appreciated, the versatility ofthe present construction sharply contrasts with the prior art machinesthat by far have sought to achieve manufacturing economy by eliminatingparts and attempting to “build-in” or otherwise integrate variouscomponents with the main support structure in one way or another,thereby forcing the manufacturer to substantially construct each machinefrom the ground up at a single location, as well as greatly limiting themachine's ability to accommodate alternative constructions withoutsignificant modification.

As suggested earlier, the invented apparatus 1 may also compriseadditional components and functional improvements if desired to suit aparticular alternative embodiment. Some of these will now be describedbelow, without limitation.

Additional Components and Improvements

As shown in FIG. 9, one improvement of the invented apparatus 1 is theheat unit sub-assembly 20 (shown in FIG. 3) that further comprises anadjustment means 58. Whereas, in one preferred embodiment the saidadjustment means 58 is a threaded insert or similar sleeve type bushingthat recesses into the hole 34 of the heater block 21; and whereas, thesaid hole 34 is threaded to accommodate the adjustment means 58; andwhereas, the said adjustment means 58 may be adjusted either up or downwithin the said hole 34 to alter the compressive force on the actuatingmeans 26 also shown in FIG. 3, thereby altering the position, and/ororientation of the heater block 21, as well as altering the compressiveforce required to initiate actuation of the said actuating means 26.

As shown in FIG. 3 and FIG. 9, another improvement of the inventedapparatus 1 is a heat unit sub-assembly 20 that further comprises atemperature probe port 55. Whereas, in one preferred embodiment the saidprobe port 55 is a hollow tube member that recesses into a desired hole56 the heater block 21 and terminates in close proximity to theinjection tube 22. In another preferred embodiment, the locking member30 that secures the injection tube 22 in the predrilled hole 29 alsofunctions as the probe port 55. The said temperature probe port 55allows the user to insert a probe from a remotely located temperaturemeasurement device and monitor the internal temperature of the heaterblock 21.

Another improvement of the invented apparatus 1 is the heat unitsub-assembly 20 further comprising a protective means. As shown in FIG.3 and FIG. 9, the said protective means in this preferred embodiment isa bracket 75 that mounts to the heater block 21 by means of screws 76and provides the electrical components of the heat unit sub-assembly 20with protection against contamination, electrical shorts, and heat loss,as well as providing a magnetic surface to accommodate a magneticallymounted a bi-metal temperature display means 59, which is evident byviewing FIG. 10. The said bracket 75 also keeps the heating elements 27from slipping out the hole 32 during operation of the invented apparatus1. It should be noted however, if the said electrical components areadequately protected and secured by other means, such as an enclosure orother protective means, the said bracket 75 may or may not be desired.

Another improvement of the invented apparatus 1 is the heat unitsub-assembly 20 that comprises a gripping means to remove the injectiontube 22 from the heater block 21. This improvement is typically employedwhen the heater block 21 is constructed with a slot 94 as illustrated inFIG. 13, rather than a predrilled hole 29 as illustrated in FIG. 3.

Accordingly, as illustrated in FIG. 15, the retaining member 104removably secures the injection tube 22 to the metal insert 95. The saidtube 22 and/or insert 95 may have a notched section 105 to accommodatethe same. A heat resistant protective shield 106, such as mica board,secures to the metal insert 95 as shown, typically by means of screws107. A knob 108 or similar gripping means secures to the protectiveshield 106. The said protective shield 106 serves to reduce the amountof heat transferred from the insert 95 and heater block 21 to the knob108, allowing the user to grip the said knob 108 without getting burned.This improvement allows the user to easily remove the injection tube 22from the heater block 21 even when the said block 21 is at operatingtemperature with the heating elements 27 energized, simply by firstremoving the dowel pins 96, and then pulling on the knob 108 to slidethe metal insert 95 and attached tube 22 out of the slot 94. The saidtube 22 can then be easily reinstalled into the slot 94 by following thesame procedure in reverse.

In an alternative, albeit more complex arrangement (not shown), thedowel pins 96 may be substituted with a locking mechanism integratedinto the heat unit sub-assembly 20. For example, in one preferredalternative embodiment, a lock bar and a compression spring areintegrated with the metal insert 95 and knob 108, such that pushing onthe knob 108 and turning it will compress the spring and rotate the lockbar. Whereas, when the said knob 108 is turned to one position the lockbar rotates until it interlocks with the heater block 21, thus securingthe insert 95 and knob 108 in place, and preventing the injection tube22 from being removed from the slot 94 in the heater block 21. And, whenthe said knob 108 is pushed in and turned to another position, the lockbar rotates out of the interlocked position, thus detaching the insert95 and knob 108 from the heater block 21, and allowing the injectiontube 22 to be removed. As previously stated, the said injection tube 22may be removably secured to the insert 95 by means of a retaining member104, but if desired it may alternatively be attached permanently to theinsert 95 by welding or brazing, or by any other desired means. Eitherway, if the tube 22 is attached to the insert 95, it allows it to beremoved along with the insert 95 and knob 108 when they are separatedfrom the heater block 21. Alternatively, if the injection tube 22 isleft unattached to the insert 95, it may be removed from the heaterblock 21 independently, which would be desirable when a single use ordisposable type injection tube 22 is employed. Using a disposable typetube 22 would typically be desirable when injecting experimental orhybrid materials, or those not easily cleaned out of the tube 22 afterinjecting.

One advantage of this alternative embodiment is that it allows the userto easily remove the injection tube 22 from the heater block 21 whilethe invented apparatus 1 is at operating temperature with the heatingelements 27 energized. Typical reasons for doing this would be to refillthe tube 22 with more injectable material, or to perform externalfunctions while the material is in its molten state, such as mixing inadditives, colorants, or fillers. Or, if the tube 22 is a single use ordisposable type, replace it with another tube 22. Once the desiredexternal functions are completed, the removed injection tube 22 can beeasily reinstalled back into the receiving slot 94 of the heater block21, and the material injected into a desired mold. FIG. 16 illustratesthe injection tube 22, injection nozzle 23, retaining member 104, metalinsert 95, protective shield 106, and knob 108 attached together.

As shown in FIG. 10, another improvement of the invented apparatus 1 isan adjustable position backing plate 52 mounted to the back wall 5 ofthe stand 2 by means of screws 53. The said backing plate 52 istypically positioned so it opposes the push plate 83 of the moldclamping means 80 and may be shimmed forward with washers 54 or similarspacers to a desired distance away from the back wall 5. The saidadjustable position backing plate 52 allows the user to easily line upthe mold (not shown) with the injection nozzle 23 relative to the saidback wall 5.

As shown in FIG. 10, another improvement of the invented apparatus 1 isa mold clamping means 80 further comprising a removable push plate face88. The said face 88 is secured to the push plate 83 by any desiredmeans, typically by means of screws or magnetically attached, and may beprovided in various sizes to accommodate the particular mold size beingused, thereby providing a more evenly distributed force against the saidmold (not shown) when clamping it. The said push plate face 88 may beconstructed from any desired material, and may be preferably heatconductive, or alternatively heat resistant to suit a particularapplication.

Another improvement of the invented apparatus 1 is a stripping means tohelp remove any residual thermoplastic material that may stick to theinjection ram. In the illustrated preferred embodiment, as shown in FIG.10, the said stripping means is a bushing 78 that press-fits into thereamed hole 14 of the nose 7 and extends slightly below the bottomsurface of the nose extension 8, such that its exposed bottom edgefunctions as a means to “strip off” any residual plastic that sticks tothe injection ram 43 when the handle 41 is lifted.

Another improvement of the invented apparatus 1 is a temperatureresponsive paint (not shown) applied to any desired surface of the saidapparatus 1 to provide the user with a visual indication when thetemperature of the said painted surface has changed.

Another improvement of the invented apparatus 1 is an illumination means(not shown), typically an LED or an incandescent lamp, integrated intothe circuitry of the invented apparatus 1. The said illumination meansis secured to the invented apparatus 1 at any desired location,preferably where it illuminates the top of the mold (not shown), toprovide the user with more visibility when aligning the said moldunderneath the injection nozzle 23.

Another improvement of the invented apparatus 1 is the handlesub-assembly 40 shown in FIG. 4 that alternatively comprises anadjustable length handle (not shown). Whereas, the said handle hasmultiple components that may include a spring loaded mechanism allowingit to be extended for added leverage when the user operates the machine,and then automatically retractable when the user lets go of it. The saidadjustable length handle may also be lockable at predetermined lengths.

Another improvement of the invented apparatus 1 is the handlesub-assembly 40 shown in FIG. 4 that alternatively comprises amulti-component injection ram (not shown). Whereas, the said ram has atleast a marginal head portion and a marginal shaft portion; and, ifdesired, the head portion may vary in length and/or diameter from thatof the shaft portion; and the head portion and shaft portion may beconstructed of similar or alternatively dissimilar materials; and thehead portion may removably attach to the shaft portion. The saidmulti-component ram being designed to reduce sticking of thermoplasticmaterials to the ram and improve the functionality and versatility ofthe injection ram 43 as it is presently shown.

As shown in FIG. 10 and FIG. 16, the invented apparatus 1 may alsocomprise a pellet tray 57 that slips over the exposed top portion ofinjection tube 22 to capture and funnel the plastic pellets (not shown)into the said tube 22. The said pellet tray 57 is desirable when theinjection tube 22 is fabricated as a substantially straight tubularmember. However, it should be noted, the said tray 57 may not be desiredif the top portion of the injection tube 22 is flared out or otherwisedesigned to accomplish the same.

As shown in FIG. 10, the invented apparatus 1 may also comprise aprotective enclosure 71 that surrounds the heat unit sub-assembly 20. Inthe illustrated preferred embodiment, the protective enclosure 71 iscomprised of two parts, a cover shield 71(a) and a top plate 71(b). Thesaid cover shield 71(a) and top plate 71(b) attach to each other bymeans of screws 73, and the protective enclosure 71 may attach to thestand 2 at any desired location by any desired means. In the illustratedembodiment, the cover shield 71(a) is secured to the side walls 6 of thestand 2 by means of screws 74. The protective enclosure 71 is desirablein many preferred embodiments as a means to protect users fromaccidentally burning themselves. However, it should be noted, inalternative embodiments, if that danger is reduced, the said enclosure71 may not be desired. For example, if the heater block 21 isconstructed partly from a composite material, or has a heat resistantshell or protective bracket 75 that minimizes its surface temperature,the protective enclosure 71 may or may not be desired.

As shown in FIG. 10, the invented apparatus 1 may comprise a temperaturedisplay means 59. The said display means 59 may be a powered device andelectrically integrated into the circuitry of the invented apparatus 1,or alternatively, and as illustrated, may be a non-powered mechanism,such as a bi-metal type thermometer. The said temperature display means59 may be attached to the invented apparatus 1 wherever desired. In onepreferred embodiment, the temperature display means 59 is mounted inclose communication with the heater block 21, which is preferable whenthe said display means 59 is a non-powered bi-metal thermometer. Inanother preferred embodiment, the said display means 59, is inelectrical communication with the temperature sensing means 28 and maybe a component of the control box sub-assembly 60, or alternatively theheat unit sub-assembly 20.

As shown in FIG. 10, the invented apparatus 1 may comprise a statusindicator 77 to monitor and/or advise the user of any desired conditionof the invented apparatus 1. In one preferred embodiment the statusindicator 77 is a lamp that lights up when the power is turned on. Inanother preferred embodiment the status indicator 77 is a lamp thatcycles on and off in synchronization with the intermittent energizing ofthe heating element 27 of FIG. 3. The said status indicator 77 ispreferably integrated into the electrical circuitry of the inventedapparatus 1, and may be attached wherever desired. FIG. 10 shows thesaid status indicator 77 as a component of the control box sub-assembly60.

As shown in FIG. 10, the invented apparatus 1 may also comprise numerousother components if desired. For example and without limitation, arubber handle grip 79 slipped onto the handle 41 for added user comfort(shown already attached); a power cord 64 hold down clip 91 mounted tothe back fin 9 of the stand 2 for added safety; an adjustable mold stop89 that removably attaches to the stand 2 to facilitate lateralalignment of the mold (not shown); an accessory holding clip (not shown)mounted to the back fin 9 of the stand 2 for added convenience. Athermostat control knob 90, for attachment to the temperature sensing(and control) means 28. The said knob 90 is preferably made of a heatresistant material, such as phenolic.

FIG. 11 shows the invented apparatus 1 with the exploded components ofFIG. 10 now attached.

Operation of the Invented Apparatus

It should first be explained, all of the elements referred to in thissection have been previously described in detail. However, because someof these elements are obstructed from view by other elements when theinvented apparatus 1 is constructed, they cannot all be shown togetherin FIG. 12, which supplements this section of the detailed description.Therefore, for a clearer view of the elements 3, 5, 7, and 9 the readeris asked to refer to FIG. 2; for a clearer view of the elements 21, 22,26, and 28 the reader is asked to refer to FIG. 3; for a clearer view ofelement 92 the reader is asked to refer to FIG. 7

Accordingly, as shown in FIG. 12, except for as already provided, in onepreferred embodiment; the invented apparatus 1 is first secured to aworkbench or table by any desired means, typically bolts 72. The handle41 is then lifted to its upright position before turning on the machine.The power cord 64 is then plugged in and the power switch 62 is turnedon. The temperature sensing (and control) means 28 is then adjusted to adesired temperature by turning the attached control knob 90 to a desiredposition, which may vary depending on the type of plastic to be melted.While waiting for the heater block 21 to reach the desired temperature,a mold 93 is positioned directly underneath the injection nozzle 23 andsecured in place by tightening the mold clamping means 80 against it.Plastic pellets (not shown) are then poured into the pellet tray 57,allowing them to funnel into the injection tube 22, and are givensufficient time to melt. The handle 41 is then pulled down by the userwith a quick, but smooth motion, causing the injection ram 43 to lowerinto the injection tube 22. When the injection ram 43 makes contact withthe thermoplastic material in the injection tube 22, the actuating means26 suspending the heater block 21 begins to compress, thus lowering theheater block 21 until the injection nozzle 23 is tightly pressed againstthe mold 93. As the user continues applying a harder downward force onthe handle 41, the melted thermoplastic material is forced out of theinjection nozzle 23 and directed into the mold 93. When the mold cavityis full, the user then lifts the handle 41 up until the catch pin 45 isreceived by the catching means 92, thereby securing the handle 41 in theupright position. It should be noted at this point, as alluded toearlier, the utility advantage of having the back fin 9 higher than theback wall 5 and nose 7 is that it allows the catch clip 92 to be mountedin close proximity with the catch pin 45 of the handle 41. Anotheradvantage of the back fin 9 configuration is that it prevents the handle41 from being lifted beyond a certain point if the catch pin 45 andcatching means 92 become misaligned with each other, or otherwise failto work. In that instance, the bottom surface of the handle 41 wouldbutt up against the back fin 9 at a predetermined point above the nose 7and back wall 5, preventing the handle 41 from being lifted any further.After the handle 41 is lifted, the mold clamping means 80 is loosenedand the mold 93 is removed from the invented apparatus 1. The two halvesof the mold 93 are then separated from each other to reveal theinjection molded article. After the user is finished using the machine,the injection tube 22 is purged of any residual plastic by simplypulling down the handle 41 with no mold in place, thereby expelling theleft over plastic onto the base 3 of the stand 2, or if desired into acontainer placed underneath the injection nozzle 23. Accordingly, Iclaim:

1. An injection molding apparatus comprising at least: a main supportstructure; a heating and injection unit assembly, characterized by areceiving slot and a removable means for containing an injectablematerial; a handle assembly; a control box assembly; a mold clampingmeans; electrical communication between at least the control boxassembly and the heating and injection unit assembly.
 2. The apparatusof claim 1 wherein a locking means secures the removable means in thereceiving slot.
 3. The apparatus of claim 1 wherein a locking means isintegrated with a removable insert and a gripping means and secures theremovable means in the receiving slot.
 4. A heating and injecting unitassembly comprising at least: a support means; a heating and injectionunit, characterized by a receiving slot and a removable means forcontaining an injectable material; a means for directing the flow ofsaid material; a means to actuate motion; a means to sense temperature;a means for external electrical connection.
 5. The assembly of claim 4comprising a locking means to secure the removable means in thereceiving slot.
 6. The assembly of claim 4 wherein a locking means isintegrated with a removable insert and a gripping means and secures theremovable means in the receiving slot.